The present invention relates to pumps.
In particular, the present invention relates to liquid pumps.
The present invention particularly relates to fuel pumps forming part of internal combustion engines. Pumps of this latter type are of course very well known. They have over the years been operated in a number of ways such as by gravity, by utilizing the Steward system which is already out of service, and by conventional mechanical drives practically universally adapted to all types of internal combusion engines. Also electrically operated liquid pumps of this latter type are known. However, such electrically operated pumps are not used to the extent of mechanically driven pumps because of the construction, operation, and maintenance costs involved in connection with electrically operated pumps.
The conventional mechanically driven liquid pumps of the above type generally include a link or lever arm which is supported for turning movement and which at one end is connected to a pumping element such as a diaphragm while the other end of this link or lever arm is actuated by a rotary cam mounted on the camshaft of the engine. Such a link or lever arm is subjected to considerable stress along its whole length and undergoes a considerable amount of wear, and at times breaks or is otherwise injured in a manner preventing the desired engine operation from going forward.
Similar although not identical problems are encountered in connection with electrically operated pumps of the above type. In addition to the above problems, the electrically operated pumps, although they may be free of mechanical stress, nevertheless require a high degree of tolerance in the manufacture of the components for energizing the system, and the calibration of electrical contacts as well as the maintenance thereof are problems encountered with this type of pump which generally requires a highly specialized technician in order to make repairs and adjustments and assure the best possible operation of such a pump. By reason of these factors such pumps are undesirably expensive.